1. Technical Field
The present disclosure relates to an optical scanning projection module.
2. Related Art
Currently, the micro-projection system technique may be classified into two categories. The first category is a laser scanning projection technique using laser light as a light source, and the second category is a digital light process (DLP) technique or a liquid crystal on silicon (LCoS) technique and uses a Light Emitting Diode (LED) as a light source.
The laser light has a wider color gamut and better color saturation, so the micro-projection system (hereinafter named by the laser scanning projection system) employing a laser as the light source is capable of projecting brighter and more colorful frames. Furthermore, as the laser light has high brightness, good directivity, and may be projected on any plane, the complicated focus lens set is not required when the laser is used as the light source. Accordingly, the structure of the laser scanning projection system can be simplified, and the laser scanning projection system is minimized and may be installed in an electronic device easily.
Since the laser is a high-power light source, it is required for the laser scanning projection system to strictly conform the laser safety standard. Generally, the laser scanning projection system meets the laser safety standard in normal operation. However, when the scanning element (i.e. the micro-mirror) is faulty and cannot control the laser light to form a frame, a single light spot having high brightness is formed and is hazardous to the viewer's eyes. Moreover, the rotation amplitude of the laser scanning projection system associates with the incident light power. During the laser scanning projection system performing the dynamic projection, the content of the frames to be projected changes quickly, so the power of the laser light is changed with the content. Herein, the temperature of the scanning element changes quickly, and so does the rotation amplitude of the scanning element. This causes two adjacent scanned frames cannot be matched. As a result, the image distortion and the frame blur are caused.